@venkat我不能发表评论，这就是为什么我把这个作为答案。你的代码在本地工作吗？如果它是工作，那么正如你提到的，请联系去爸爸客户支持.我曾经面临过类似的问题之一的项目。他们启用一些设置和邮件开始工作。
对于TLS加密，端口号为587，对于SSL加密，端口号为465
为了更好地理解，请查看链接https://kinsta.com/blog/gmail-smtp-server/
我正在使用下面的代码，它正在为我工作。

require("./PHPMailer-master/src/PHPMailer.php");
require("./PHPMailer-master/src/SMTP.php");
$mail = new PHPMailer\PHPMailer\PHPMailer();
$mail->IsSMTP(); // enable SMTP
$mail->SMTPDebug = 0; // debugging: 1 = errors and messages, 2 = messages only
$mail->SMTPAuth = true; // authentication enabled
$mail->SMTPSecure = 'tls'; // secure transfer enabled REQUIRED for Gmail
$mail->Host = "smtp.gmail.com";
$mail->Port = 587; // or 587
$mail->IsHTML(true);
$mail->Username = "venkateshm2280@gmail.com";
$mail->Password = "mmuxhssfdrqnsowp";
$mail->SetFrom("venkateshm2280@gmail.com");
$mail->Subject = "Application for Programmer Registration";
$mail->Body = $message;
$mail->AddAddress("venkateshm2280@gmail.com", "HR");
$mail->AddAttachment( $path , 'filename' );

$headers = "From: Sender\n";
$headers .= 'Content-Type:text/calendar; Content-Disposition: inline; charset=utf-8;\r\n';
$headers .= "Content-Type: text/plain;charset=\"utf-8\"\r\n"; #EDIT: TYPO

if (!$mail->Send()) {
    echo "Mailer Error: " . $mail->ErrorInfo;
} else {
    echo "Message has been sent";
}

试试下面的代码。

require_once 'PHPMailer/class-phpmailer.php';
$mail = new PHPMailer();

$options["ssl"] = array(
    "verify_peer" => false,
    "verify_peer_name" => false,
    "allow_self_signed" => true,
);
$mail->SMTPDebug = false;
$mail->isSMTP();
$mail->Host = 'tls://smtp.gmail.com'; // This line was missing.
$mail->SMTPAuth = true;
$mail->Username = 'venkateshm2280@gmail.com';
$mail->Password = 'mmuxhssfdrqnsowp';
$mail->SMTPSecure = 'tls';
$mail->Port = '587';
$mail->smtpConnect($options); // try with this line.
$mail->setFrom($_POST['email'], $_POST['name']);
$mail->AddAddress('venkateshm2280@gmail.com');
$mail->isHTML(true);
$mail->Subject = 'Application for Programmer Registration';
$mail->Body = $message;
if (!$mail->send()) {
    $finalResponse = 'Message could not be sent. Mailer Error: ' . $mail->ErrorInfo;
} else {
    $finalResponse = 'success';
}